The present invention relates to a disk brake for a bicycle, and more particularly to a brake caliper for a bicycle disk brake which can easily be adjusted to change the pitch between two arms of the crank lever thereof, so as to achieve a positive brake operation.
A regular bicycle may be equipped with a disk brake, and operated to stop the bicycle from movement. A conventional bicycle disk brake is generally comprised of a brake disk fixedly fastened to the hub at the front fork of the bicycle, and a brake caliper mounted on lugs at the front fork and driven by a brake line to stop the brake disk from rotation. The brake caliper, as shown in FIGS. 1, 2 and 3, comprises a brake caliper base having two receiving chambers at two opposite sides of the brake disk, two cam shafts respectively mounted in the receiving chambers inside the base, two brake linings respectively fastened to the cam shafts by screws, and a crank lever having a substatially U-shaped head connected to the brake cable and two arms respectively extended from the two opposite ends of the U-shaped haed and connected to the cam shafts outside the brake caliper base. This structure of brake caliper is functional, however it still has drawbacks. Because the crank lever is made by stamping a steel plate into shape, the spring power of the arms of the crank lever become worse after a long use. Because the pitch between the arms of the crank lever is not adjustable, the crank lever does not function well when the spring power of the arms become worse.
The present invention has been accomplished to provide a brake caliper for a bicycle disk brake which eliminates the aforesaid problem. It is the main object of the present invention to provide brake caliper for a bicycle disk brake, which can be conveniently adjusted to fit the spring power of the arms of the crank lever, enabling a brake action to be positively achieved. According to the present invention, an adjustment device is provided for adjusting the pitch between the arms of the crank lever, enabling the crank lever to be positively driven by the brake cable to achieve a brake action. The adjustment device comprises a screw rod threaded into a screw hole at one of the two shoulders of the crank lever and engaged into a recessed locating hole at the other of the two shoulders of the crank lever, and a nut threaded onto the screw rod and rotated to move the screw rod for changing the pitch between the shoulders (arms) of the crank lever.